Question on "unprintable area"

Archived from groups: comp.periphs.printers (More info?)

When I preview MS Access reports using an impact printer driver, the
margin (usuaily the right-margin is automatically adjusted), even thogh
the report is less than the maximum.

After automatic adjustment, the width becomes larger than the maximum,
and thus scrolls down (ie produces a page with partial printout).

Can someone explain why does this happen ?

Thanks.